S-Alkenyl and -alkynyl carbohydrate derivatives were prepared from 1,2:5,6-O-diisopropylidene-α-D-allofuranose. Nitrones and nitrile oxides generated from these derivatives led to the formation of 6, 7, and 11-membered chiral sulfur heterocycles fused to isoxazolidine, isoxazoline and isoxazole rings. Some of these sulfur heterocycles were converted to nucleosides. The 11-memebered sulfur compound was found to gelate hydrocarbon solvents.